Certain devices having oil crankcases, such as small internal combustion engines, are designed for a variety of applications in commercial and residential settings. Exemplary applications for engines included in this category include driving paint sprayers, air compressors, power high pressure water washers, small electrical generators, and lawn and garden tools such as roto-tillers and lawn mowers. These engines tend to be small displacement, 4 cylinder gasoline driven engines having a single cylinder or two cylinders. I will refer to the engines used in these exemplary devices as "small engines". Typically a manufacturer of one of these devices will purchase the engine separately from the object to be driven by the engine, and will then mount the components together on a platform or chassis as part of the final assembly. In order to provide a solid, vibration resistant platform, as well as to keep manufacturing costs low, the chassis on which the components are mounted is frequently a single piece of steel plate, a cast metal platform, or a stamped metal platform. The chassis can also comprise an open framework.
In order to lubricate the internal components of the engine or gearbox, as for example, the crankshaft in an engine, the device includes a crankcase for holding lubricating oil. To ensure that the maximum amount of oil is removed from the crankcase when the oil is changed, a drain point is located low in the crankcase. In automotive engines, the drain point is normally located at the bottom of the oil pan, allowing the draining of oil from the lowest possible point. However, in small engine applications and the like, since the engine or device is typically mounted on a solid platform as discussed above, a bottom drain plug is impractical. Such would require the assembler of the finished product to provide for a drain plug opening in the platform. Additionally, in applications such as a roto-tiller, a bottom drain plug would be difficult to access due to the presence of the tines of the roto-tiller beneath the engine. Consequently, small engine manufacturers and others have taken to positioning the crankcase oil drain plug on the side of the engine or gearbox, as low as possible, to allow for the maximum amount of oil to be drained without requiring the assembler to accommodate a bottom drain plug, or the end user to access a bottom drain plug.
FIG. 1 shows an exemplary device which uses a small engine of the type described above. The device 2 is a power washer which pumps water at high pressure through a hose for washing sidewalks and the like. The device 2 comprises a pump 3 which is driven by a small engine 4. The pump 3 and engine 4 are mounted on a platform 5, which, as shown here, is a solid metal plate. Located towards the bottom of the engine 4 is the oil crankcase 8. An oil drain location 9 is located at the lower side of the crankcase 8. It is immediately apparent that when a drain plug is removed from the oil drain hole 9, oil will pour across the platform 5. Beyond the obvious problems this presents in recovering the draining oil, it also requires a significant amount of clean-up to remove the oil from the device, it results in unnecessary human exposure to used oil, and it can present an environmental hazard.
Some solutions to this problem have been offered by the manufacturers. However, they do not practically solve the problem. For example, tipping the device 2 to which the engine 4 is mounted in the direction of the drain hole 9 while draining the crankcase 8 may help to direct oil runoff to one edge of the platform, but is difficult for one person to perform this act alone, and the results are still far less than perfect. Further, because of the proximity of the oil drain outlet 9 to the platform 5, positioning a container near the drain hole 9 is difficult, and unless the apparatus 2 is tipped on its side, it is of little value in collecting the draining oil. Likewise, providing a hole in the platform 5 near the crankcase drain hole 9 does not help much, as oil tends to course out of the drain hole and past the hole in the platform when the drain plug is initially removed. Also, providing such a hole in the platform is of little help for a device having significant under-platform components, such as a roto-tiller. Positioning the engine 4 closer to the edge of the platform 5 is not really an option, as this would result in uneven weight distribution of the components on the platform, and may not even be possible depending on the configuration of the device to which the engine is to be coupled.
Thus, what is needed is something to allow oil to be easily drained from a platform mounted, side-draining crankcase, and which allows the oil to be easily collected into a receptacle while producing minimal spillage of the oil.